Field
Embodiments of the present invention generally relate to methods and apparatuses for removing contaminants and oxides from a substrate surface.
Description of the Related Art
Integrated circuits are formed in and on silicon and other semiconductor substrates. In the case of single crystal silicon, substrates are made by growing an ingot from a bath of molten silicon, and then sawing the solidified ingot into multiple wafers. An epitaxial silicon layer may then be formed on the monocrystalline silicon wafer to form a defect free silicon layer that may be doped or undoped. Semiconductor devices, such as transistors, are manufactured from the epitaxial silicon layer. The electrical properties of the formed epitaxial silicon layer will generally be better than the properties of the monocrystalline silicon substrate.
Surfaces of the monocrystalline silicon and the epitaxial silicon layer are susceptible to contamination when exposed to typical wafer fabrication facility ambient conditions. For example, a native oxide layer may form on the monocrystalline silicon surface prior to deposition of the epitaxial layer. Additionally, contaminants present in the ambient environment may deposit on the monocrystalline surface. The presence of a native oxide layer or contaminants on the monocrystalline silicon surface negatively affects the quality of an epitaxial layer subsequently formed on the monocrystalline surface. Mile present cleaning methods remove some of the native oxides and contaminants from the monocrystalline silicon surface, some contaminants still remain.
Therefore, there is a need for a method and apparatus for cleaning a substrate surface, especially for cleaning a substrate surface prior to performing an epitaxial deposition process.